Ramsey-like fringes observation during excitation of coherent modes in a Bose-Einstein condensate Original Research Article

In this work we analyse the excitation of coherent modes for different modalities for the time domain application of the external excitation. We have employed a single pulse excitation or a double pulse excitation. The population dynamic was analysed as a function of the frequency detuning between the modes energy separation and the external field frequency. For a single pulse, a Rabi like resonance profile was observed with maximum population transfer off resonance due to the strong non-linearity in the system. Line-shape as well as amplitudes are analysed. For a double pulse excitation, the occurrence of probbability interference generates a Ramsey-fringe like resonance with a considerable narrowing of the central line. Such profile has been investigated as a function of the delay between pulses revealing a dependence of the fringes distribution. It is found that the Ramsey pattern itself retains information about the accumulated relative phase between both ground and excited coherent modes.